This invention relates to a torque-testing instrument for tools. More particularly, the tool is fastened in a testing instrument and subjected to a torque effect. The torque applied to the tool is detected or picked up via a measuring instrument from which measured values are transmitted to a reading device, or the like, by means of transmission elements. Testing instruments of different kinds are used for testing the torque resistance of tools, such as spanners, wrenches and the like. Testing instruments having a spring dynamometer operable pneumatically or manually are known. Purely mechanically operating torque-testing instruments do not work with sufficient accuracy. Furthermore, the elasticity in the mechanical torque-testing instruments may grow weaker with use. Comparatively significant discrepancies in measurements occur. Consequently, these known instruments can give only a rough indication for the torque resistance of the tool being tested.
Other torque-testing instruments work on the principle of the application of a wire strain gauge. In this known type of instrument, a different wire strain gauge has to be applied for each torque value. The measuring ranges of the instrument are comparatively small. Different capsule-type dynamometers with corresponding wire strain gauges have to be applied at any given time for different measuring ranges. Interchanging of this nature is inconvenient and, furthermore, in itself, conceals sources of error.
Indicating instruments with scales and pointers are used with the known torque-testing instruments. It is extremely difficult to read the results from such indicating instruments. The readings from these instruments are also repeatedly inaccurate.